Digital Guitar Effect Modeling

The book in question was formerlly presented as a M. Sc. Thesis in 2006 at Geogia Isntitute of Technology (and avaliable in internet for free). The main idea is nice but all the work are based on a mistake: The AC128 spice model. The Gummel-Poon spice model presented by the author doesn't work as desired. This is because the author just picked up some silicon transistor model and changed the Beta and forward bias voltages (Vje and Vjc) parameters for values related with germanium transistors. According to the author, the rest in the model was kept the same. The result is that in simulations using the author's model(I biased the transistor to have a VCE of 4.0V and Ic of 1.5mA) the Vbe of this transistor, which would be around 0.2V, is actually around 0.7V. In other words, the spice model behave as a silicon transistor and not as a germanium transistor. This leads to a totally diferent results from the desired or the reality. Sorry. A good idea but a bad implementation of that. The advisor of this thesis should had reviewed that simple question...Don't buy this book...